The invention relates to the protection of electrical wires passing through an opening, for example by the use of grommets, and in particular to grommets suitable for use in small electric motors. While having particular application to stepping motors having two coil assemblies, and still more particularly to those with inner field cup assembly and two outer field cups, the invention also has application to other apparatus.
It is conventional to use two axially adjacent stator coils which are disposed in a central stator portion formed by two inner field cups, the inner field cups and coils then constituting an inner field cup assembly. Two outer field cups or corners nest around the axial extremeties of the inner field cup assembly. The wires leading from the stator coils pass through aligned wire openings in the inner field cup assembly and the outer field cups. Ordinarily a first grommet is threaded around the wires leading from one of the coils and protects the wires as they pass sequentially through the opening in the inner field cup assembly and the opening in the outer field cup aligned with that particular coil. The wires from the other coil are threaded through a second grommet and that grommet is installed in the other outer field cup and the portion of the inner field cup assembly associated with the second coil.
Difficulties are experienced in some cases because one or both of the discrete grommets may not seat properly in the outer field cup or inner field cup. This may not become apparent until after the outer field cup has been pressed in place. The separation of the outer field cup after it has been pressed into place is difficult and time consuming.